1. Field of the Invention
The invention relates to a drum type washing machine comprising a perforated washing drum being suspended for rotation within a cylinder-shaped tank having at least one inlet for inflow of cold water and one outlet for waste washing water, and may furthermore incorporate one or several heating elements intended for heating of the supplied cold water.
2. Description of the Prior Art
It is in such washing machines known that the discharged waste washing water may be directed through a separate heat exchanger in such a manner that part of the heat conveyed to the discharged water can be restored. Separate heat exchangers of this type are, however, expensive compared to the quantity of heat they may restore. Moreover a separate heat exchanger of traditional construction will often be choked up by fibres and particles worn off the laundry during the washing process which will result in a reduction of the efficiency of the heat exchanger and require frequent time-consuming cleaning.